perf: final sweep — hot-path allocation, cached log target, sort-header skip

Last round of targeted wins:

  - upload-manager progress callback was allocating a fresh
    { jobId, speedKbs, bytesUploaded } object on every fs stream chunk
    (hundreds of times per second per active job). Now a single entry
    is created at job start and mutated in place — zero allocations
    on the steady-state progress tick.

  - upload-manager stats timer's two separate activeJobs.values()
    scans (globalSpeedKbs + inProgressBytes) merged into one pass.

  - clouddrop-upload.js reuses a single Buffer.allocUnsafe(chunkSize)
    across all chunks, taking subarray() only for the tail chunk.
    A 1 GB upload no longer allocates 64× 16 MB = 1 GB of short-lived
    buffers — real GC relief during many-file batches.

  - _resolveUploadLogTarget is now cached; the fallback ladder runs
    once per session (or when the user changes the log path / daily-log
    date rolls), not on every 500ms flush.

  - renderRecentUploadsPanel skips updateRecentSortHeaders on the
    append-only fast path — sort state hasn't changed, headers don't
    need recomputing.

lib/clouddrop-upload.js

@@ -155,9 +155,13 @@ class ClouddropUploader {
     const totalChunks = initPayload.totalChunks || Math.ceil(fileSize / chunkSize);
     if (!sessionId) throw new Error('Clouddrop: Keine sessionId von /upload/init');
 
-    // 2. Read file and PUT chunks sequentially
+    // 2. Read file and PUT chunks sequentially.
+    // Reuse a single buffer for all chunks (only the last chunk may be smaller,
+    // in which case we slice a view). Avoids 64× 16 MB allocations on a 1 GB
+    // file — real GC pressure during busy uploads.
     const fd = fs.openSync(filePath, 'r');
     let bytesSent = 0;
+    const reusableBuf = Buffer.allocUnsafe(chunkSize);
     try {
       for (let i = 0; i < totalChunks; i++) {
         if (signal && signal.aborted) throw new Error('Aborted');
@@ -165,8 +169,10 @@ class ClouddropUploader {
         const offset = i * chunkSize;
         const remaining = fileSize - offset;
         const thisChunkSize = Math.min(chunkSize, remaining);
-        const buf = Buffer.alloc(thisChunkSize);
+        fs.readSync(fd, reusableBuf, 0, thisChunkSize, offset);
-        fs.readSync(fd, buf, 0, thisChunkSize, offset);
+        const body = thisChunkSize === chunkSize
+          ? reusableBuf
+          : reusableBuf.subarray(0, thisChunkSize);
 
         if (throttle) await throttle.consume(thisChunkSize, signal);
 
@@ -174,7 +180,7 @@ class ClouddropUploader {
           method: 'PUT',
           dispatcher: clouddropAgent,
           signal,
-          body: buf,
+          body,
           headers: this._headers({
             'Content-Type': 'application/octet-stream',
             'Content-Length': String(thisChunkSize)

lib/upload-manager.js

@@ -361,7 +361,11 @@ class UploadManager extends EventEmitter {
             }, 2000);
           }
 
-          this.activeJobs.set(uploadId, { jobId, speedKbs: 0, bytesUploaded: 0 });
+          // Mutate this single object on each progress callback instead of
+          // allocating a fresh one — callback fires on every stream chunk
+          // (hundreds/sec per active job).
+          const activeEntry = { jobId, speedKbs: 0, bytesUploaded: 0 };
+          this.activeJobs.set(uploadId, activeEntry);
 
           let lastEmitTime = 0;
           const PROGRESS_EMIT_INTERVAL = 250; // ms – throttle UI updates
@@ -377,7 +381,8 @@ class UploadManager extends EventEmitter {
               lastSpeedTime = now;
             }
 
-            this.activeJobs.set(uploadId, { jobId, speedKbs: currentSpeedKbs, bytesUploaded });
+            activeEntry.speedKbs = currentSpeedKbs;
+            activeEntry.bytesUploaded = bytesUploaded;
 
             // Throttle progress emissions to reduce IPC + rendering overhead
             if (now - lastEmitTime < PROGRESS_EMIT_INTERVAL) return;
@@ -582,18 +587,17 @@ class UploadManager extends EventEmitter {
   _startStatsTimer() {
     if (this.statsInterval) clearInterval(this.statsInterval);
     this.statsInterval = setInterval(() => {
+      // Single pass over active jobs instead of two.
       let globalSpeedKbs = 0;
       let activeCount = 0;
+      let inProgressBytes = 0;
       for (const job of this.activeJobs.values()) {
         globalSpeedKbs += job.speedKbs || 0;
+        inProgressBytes += job.bytesUploaded || 0;
         activeCount++;
       }
 
       const elapsed = Math.round((Date.now() - this.startTime) / 1000);
-      let inProgressBytes = 0;
-      for (const job of this.activeJobs.values()) {
-        inProgressBytes += job.bytesUploaded || 0;
-      }
 
       this.emit('stats', {
         state: this.running ? (this.stopAfterActive ? 'stopping' : 'uploading') : 'idle',

main.js

@@ -165,12 +165,33 @@ const _uploadLogBuffer = [];
 let _uploadLogFlushTimer = null;
 let _uploadLogWriting = false;
 
+// Cache the resolved upload-log target across flushes — mkdirSync + path
+// assembly on every 500ms flush during uploads is wasted work once we've
+// confirmed a writable directory. Invalidated when the user changes the log
+// path or when the daily-log date rolls over.
+let _cachedUploadLogTarget = null;
+let _cachedUploadLogKey = '';
+
+function _invalidateUploadLogTargetCache() {
+  _cachedUploadLogTarget = null;
+  _cachedUploadLogKey = '';
+}
+
 function _resolveUploadLogTarget() {
-  // Try primary → desktop → userData, mirror the original fallback ladder.
   const primary = getLogFilePath();
+  const key = `${primary}|${_dailyLogDate || ''}`;
+  if (_cachedUploadLogKey === key && _cachedUploadLogTarget) return _cachedUploadLogTarget;
+
+  const commit = (t) => {
+    _cachedUploadLogTarget = t;
+    _cachedUploadLogKey = key;
+    return t;
+  };
+
+  // Try primary → desktop → userData, mirror the original fallback ladder.
   try {
     fs.mkdirSync(path.dirname(primary), { recursive: true });
-    return { path: primary, isFallback: false };
+    return commit({ path: primary, isFallback: false });
   } catch (err) {
     debugLog(`uploadLog primary dir unavailable (${err.message})`);
   }
@@ -179,13 +200,13 @@ function _resolveUploadLogTarget() {
     try {
       const p = buildFallbackLogName(desktop);
       fs.mkdirSync(path.dirname(p), { recursive: true });
-      return { path: p, isFallback: true };
+      return commit({ path: p, isFallback: true });
     } catch {}
   }
   try {
     const p = buildFallbackLogName(app.getPath('userData'));
     fs.mkdirSync(path.dirname(p), { recursive: true });
-    return { path: p, isFallback: true };
+    return commit({ path: p, isFallback: true });
   } catch (err) {
     debugLog(`uploadLog: no writable target (${err.message})`);
     return null;

renderer/app.js

@@ -3264,6 +3264,7 @@ function renderRecentUploadsPanel() {
     && rows.length > _recentLastRenderedLen
     && tbody.querySelectorAll('.recent-file-row').length === _recentLastRenderedLen;
 
+  let wasAppendOnly = false;
   if (dateDescAppendOnly) {
     // Fast path: only new rows (date desc puts newest on top) — insert them
     // at the top without rebuilding the 5000-row tbody below.
@@ -3271,6 +3272,7 @@ function renderRecentUploadsPanel() {
     let html = '';
     for (let i = 0; i < added; i++) html += _buildRecentRowHtml(rows[i]);
     tbody.insertAdjacentHTML('afterbegin', html);
+    wasAppendOnly = true;
   } else {
     tbody.innerHTML = rows.map(_buildRecentRowHtml).join('');
   }
@@ -3316,7 +3318,8 @@ function renderRecentUploadsPanel() {
     });
   }
 
-  updateRecentSortHeaders();
+  // Sort headers only change when the sort state changes — skip on appends.
+  if (!wasAppendOnly) updateRecentSortHeaders();
 }
 
 function renderHistoryTable(container) {